Interpolymers of castor-oil maleate



Patented May 1, 1951 INTERPOLYMERS F CASTOR-OIL MALEATE Pliny 0. Tawney, Passaic, N. J assignor to United States Rubber Company,

New York, N. Y., a

corporation of New Jersey No Drawing. Application March 18, 1949, Serial No. 82,298

16 Claims. (01. 260-23) This invention relates to a method of increasing the yield of soluble, convertible polymeric materials obtained from the copolymerization of a castor-oil maleate and copolymerizable mono olefinic compounds. More particularly, my invention comprises copolymerizing a caster-oil maleate with at least one copolymerizable monoolefinic compound, in the presence of a cyclic terpene hydrocarbon, whereby high yields of soluble, unsaturated convertible resins are obtained which are new ternary interpolymers.

Copolymers of Castor-oil maleates with monoolefinic compounds, e. g., styrene, are in many respects well adapted to the preparation of coating' and laminating compositions which, after application, can be cured to a solventand heatresistant state. In this connection they are particularly suitable for blending with other thermosetting resins, e. g, urea-formaldehyde resins, and melamine-formaldehyde resins to secure more flexible products. However, such resins derived from castor-oil maleates of high acid number, e. g., 50- -l00, i. e., those containing relatively large amounts of maleic acid ester groups (such as are obtained, for example, from the reaction of one mole of caster-oil with 2-3 moles of maleic anhydride in a manner well known to those skilled in the art), tend to form an insoluble gel during the copolymerizaticn reaction, and before more than a minor proportion ofmonomers has been converted to the copolymeric form. Such products are of limited commercial utility since the presence of the masses of insoluble gel effects discontinuities in the resulting coating or laminate such as cracks, lumps and blisters. A soluble resin can be obtained, albeit in lowflyiel-ds, by halting the copolymeriza tion prior to gelation, although the large amounts of unreactedmonomeric starting materials remaining must be removed, purified and recycled for use in subsequent copolymerization in order to achieve some degree of economic-feasibility. The copolymerization of castor-oil maleates of relatively low acid number, e. g., 20-40 (such as can be obtained from the reaction of 0.3-9.6 mole of maleic anhydride with one mole of castoroil), with styrene shows a diminished tendency toward premature gelation but the resulting resins are softer, less mar-resistant and often require more stringent curing conditions to achieve a satisfactory degree of solventand heat-resistance in the final product than those derived fromthe caster-oil maleates of higher acid number. 1 I have now discovered that when a castor-oil 2 maleate is inter-polymerized with styrene in the presence of an appreciable amount of a cyclic terpene hydrocarbon, marked increases in the yield of soluble resins, which are new ternary chlorostyrene.

interpolymers, can thereby be obtained. More- I over, I have unexpectedly found that as the amount of the interpolymerizable terpene in the initial reactant mixture is increased, the amounts of the castor-oil maleate and styrene converted to the soluble polymeric form are likewise'increased. Suitable cyclic terpenes include, e.'g.,' the methenes, terpinenes, limonene, dipentene, alpha-pinene and mixtures thereof, especially turpentine. These cyclic terpenes have the general formula ClOHlG and are unsaturated. Although styrene has been cited above as illustrative of the monoolefinic compounds which are suitable for copolymerization with castor-oil maleates in the method of my invention, various substitute-d styrenes may also be employed-me cluding the alphaand para-substituted styrenes, e. g., p-chlorostyrene, p-methylstyrene, alpha, p-dimethylstyrene, p-fiuOrostyrene, p-trichloromethylstyrene, p-methoxystyrene, and 2,5-di- The styrenes can be replaced in whole or part'by other monoolefinic hydrocar= bons, e. 'g., vinylnaphthalene and aliphaticv olefinic hydrocarbons, especially the lower aliphatic olefinic hydrocarbons, i. e., those having from' 2 to 6 carbon atoms, e. g., ethylene, propylene and isobutylene, although many of the more reactive olefins sufier the economic disadvantage or" being gases at room temperature and hence they will require pressurized'equipment for the co polymerization reaction.

Other suitable monoolefinic compounds which may be used in place of styrene but which tend to yield softer resins include vinyl mono-esters of non-chic acids, e. g., vinyl acetate, vinyl butyrate and vinyl benzoate, and monovinyl ethers, e. g., vinyl ethyl ether, vinyl propyl ether and vinyl benzyl ether, and the esters of monoolefinic monocarboxylic acids with non-enic alcohols, e. g., methyl acrylate, n-butyl' acrylate, tolyl acrylate, methyl methacrylate, n-ethyl chloroacrylate and methyl crotonate. The monoolefinic acids themselves can be employed although the resulting resins are more sensitive to water and other hydroxylic solvents and to alkali. Besides esters other hydrolyzable derivatives of such monoolefinic acids can be employed, such as acid chlorides, nitriles and amides, the two latter yielding resins which are harder but are compatible with fewer solvents.

The castor-oil maleates, as is well known to those skilled in the art, are prepared by the case. The reaction mixtures are then diluted esterification of maleic acid or maleic anhydride with an excess of methanol and the precipitated with castor-oil. Usually about 1 mole of castorinterpolymers are thoroughly washed with methoil is employed per mole of maleic anhydride. anol before drying in vacuo to constant Weight.

This invention also contemplates the employ- 5 Table I below summarizes the amounts of the ment of caster-oilesters'obtainedaby substitution olefi'nie: compound (100' parts ofthe castor-oil of some or all of the maleic anhydride by the maleate being used in all cases), the cyclic terhornologues of meleic acid, such as citraconic pene, peroxide, and the resulting soluble interacid or citraconic anhydride. If desired, various polymer, as well as the reaction times. To emmodifying ingredients, such as linseed oil, maybe phasizethe advantage of my method, examples present in the reaction mixture during the prep-- of prior art copolymerization in the absence of aration of the ester to be employed in this incyclic terpene hydrocarbons are also included vention. (I-a, b; h).

Table I Reaction Soluble Olefinic Compound 'lerpone Or Solvent 553 853 Time, Interhrs. Polymer a Styrene 121 1.1 4.7 15.2

c; -Styrenc 121.. Turpentine, 81. 3. 02 7.4 40.0

d... Styrene 121 Turpentine, 161.5 3. 83 18.2 63.8

.Styrenelill Turpentine, 325.0 16.4 64.0 14320 f Styrene 121 Dipentene,325' 8.15 87.0 42.3

g ,Styrene l2l Alpha-Pinene, 318.. 8.00 54.0 J4. 6

12...- :Vinyl Acetate 100 Turpentine, 326 18.3 71.0 39.8

1 N o evidence of incipient gelation.

V In the practice of my invention, a caster-oil Comparison of La with Icabove shows that maleat'e,. preferably one having an acid numthe presence of even relatively small amountsber'offroin. about 30 to 100, is reacted with of the interpolymerizable cyclic terpene hydroi'ibmOLS'to-ZO, particularly 3 to 12, moles of a carbon in the interpolymerization of Castor-oil copolymerizable monoolefinic compound (per maleates with the designated monoolefinic commole of caster-oil maleate) in the presence of pounds-effects a very significant increase in the from about 6' to I20 moles,'especially 6 to 30 yield of soluble interpolynieric product. Sucmoles, of a cyclic, terpenehydrocarbon per mole eeeding examples indicated the further increase of the castor-oil maleate. The reaction proin yields of the soluble inter-polymer obtainable (r e s e d y t t pe s e range 25120' from reaction mixtures containing large proper-- Cl,,-preferably 40-100 C., for a time suiiicient'to 40 tions of the cyclic terpene hydrocarbon. form at least an appreciable quantity of the soluble interpolymer. Suitable reaction times EXAMPLEZ I will usually be found to be in the range of from A mixture of 54 parts of castor-oil male'ate" o to 90 hours. Suitable promoters or catalysts (acid number, 7 1), 63 parts of styrene and 280 for the reaction include conventional sources of parts of turpentine is heated at 83- C. for 14: free radicals such as organic peroxides, e. g1, hours during which time 4 two-part increments benzoyl' peroxide, acetyl peroxide and tertiaryof benzoyl'peroxide are added from time to time. butyl hydroperoxide, in amounts of from about About 63.4 parts of' acetone-soluble interpoly 0.1. to 10.0% by weight of the copolymerizable' remer are obtained; actants. A mixture of 5129 parts of a 33.1% solution of In the interpolymerization reaction, the inthe above interpol'ymer inxylene and 1.36 parts creasing viscosity of the reaction mixture can of a 54.8% solution of a commercial urea-formbe employed. as a measure of the extent of the aldehyde resin in xylene is thinned with a small reaction. The resulting soluble interpolymer can amount of' 1:1 (by Weight) mixture of Xylene be isolated from the reaction mixture by evaporaand butanol. The solution is spread onto a glass tion-of the cyclic terpene? hydrocarbon or by' pre- 5 plate and baked at 150 C. for 30' minutes toyield cipitationof the interpolymer through addition a hard, tough, clear film which is insoluble in of a non-solvent, e.. g., methanol. Xylene and'butanol'.

The resulting resins can be dissolved in appro- Having thus' described my' invention, what- I priate solvents, e. g., acetone, Xylene; orwby mixclaim and desire to'protect by Letters Patent is:- tures thereof and employed as coating, impreg- 1. A methodwhich comprises heating a mixnating or laminating compositions, either alone ture of '6 to 120 moles of a cyclic terpene hydroorin conjunction with" other polymeric materials carbon, 1 mole of an ester of cast'or oil and an such as urea-formaldehyde resins Upon appli-- unsaturated dibasic organic acid selected from cation of' heat, these compositions are converted the group consisting of" maleic acid and its to a solventand heat-resistant state. homologues, said ester having an acid number The following example discloses my invention of 30 to 100, and 0.5 to 20 moles of another co in more detail. All parts are by weight. polymerizable monoolefinic compound at a temperature of 25 to 120 C. in the presence of an EXAMPLE 1 organic peroxidic polymerization catalyst in Castor-oil maleate (acid number, 54) isinteramount of from 0.1 to 10.0% by weight of the: polymerized with styrene or vinyl acetate, resaid reactants. whereby a fusible, convertible 111- spectively, in the presence of various cyclic terinterpolymer of the said reactantsis formed. penes. The reactions are carried out at 60 C. 2. A method which comprises heating a mix-'- in the presence of benzoyl peroxide, until the ture of 6 to 30 moles of a cyclic terpene-hydro point of incipient gelation' is attained in each carbon; 1 molei'ofa castor-oilrjmaleate' having an acid number of 30 to 100, and 3 to 12 moles of another copolymerizable monoolefinic compound at a temperature of 40-100 C. in the presence of an organic peroxide polymerization catalyst in amount of from 0.1 to 10.0% by weight of the aforesaid reactants, whereby a soluble, convertible interpolymer of said reactants is formed.

3. A method as in claim 2 in which the cyclic terpene hydrocarbon substance is turpentine.

4. A method as in claim 2 in which the cyclic terpene hydrocarbon is alpha-pinene.

5. A method as in claim 2 in which the cyclic terpene hydrocarbon is dipentene.

6. A method as in claim 2 in which the cyclic terpene hydrocarbon substance is turpentine and the additional copolymerizable monoolefinic compound is styrene.

7. A method as in claim 2 in which the cyclic terpene hydrocarbon is turpentine and the additional copolymerizable monoolefinic compound is vinyl acetate.

8. A method as in claim 2 in which the cyclic terpene hydrocarbon is turpentine and the additional copolymerizable monoolefinic compound is a lower aliphatic monoolefinic hydrocarbon.

9. A soluble convertible interpolymer of a cyclic terpene hydrocarbon, an ester of caster-oil and an unsaturated dibasic organic acid selected from the group consisting of maleic acid and its homologues, said ester having an acid number of 30 to 100, and another copolymerizable monoolefinic compound.

10. An interpolymer of a cyclic terpene hydrocarbon, a castor-oil maleate, and another co- 85 polymerizable monoolefinic compound.

11. An interpolymer as in claim 10, in which the cyclic terpene hydrocarbon substance is turpentine.

12. An interpolymer as in claim 10, in which the cyclic terpene hydrocarbon is alpha-pinene.

13. An interpolymer as in claim 10, in which the cyclic terpene hydrocarbon is dipentene.

14. An interpolymer as in claim 10, in which REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,439,953 Swiss et a1. Apr. 20, 1948 FOREIGN PATENTS Number Country Date 573,809 Great Britain Dec. '7, 1945 580,912 Great Britain Sept. 24, 1946 

1. A METHOD WHICH COMPRISES HEATING A MIXTURE OF 6 TO 120 MOLES OF A CYCLIC TERPENE HYDROCARBON, 1 MOLE OF AN ESTER OF CASTOR-OIL AND AN UNSATURATED DIBASIC ORGANIC ACID SELECTED FROM THE GROUP CONSISTING OF MALEIC ACID AND ITS HOMOLOGUES, SAID ESTER HAVING AN ACID NUMBER OF 30 TO 100, AND 0.5 TO 20 MOLES OF ANOTHER COPOLYMERIZABLE MONOOLEFINIC COMPOUND AT A TEMPERATURE OF 25* TO 120* C. IN THE PRESENCE OF AN ORGANIC PEROXIDIC POLYMERIZATION CATALYST IN AMOUNT OF FROM 0.1 TO 10.0% BY WEIGHT OF THE SAID REACTANTS, WHEREBY A FUSIBLE, CONVERTIBLE ININTERPOLYMER OF THE SAID REACTANTS IS FORMED. 